To meet the demand for wireless data traffic having increased since deployment of 4th generation (4G) communication systems, efforts have been made to develop an improved 5th generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
Handover and Radio Link Failure (RLF) are independently operated processes in a mobile communication system. The RLF can be declared during a handover process. In this case, an attempted handover process fails, and Radio Resource Control (RRC) connection re-establishment is conducted. Since an RRC connection re-establishment process takes relatively much time compared with the handover process, its service interruption time is lengthened.
Meanwhile, in recent, the handover and the RLF concurrently take place more frequently in a heterogeneous network including a macro cell and a small cell. Hence, as the RLF is declared during handover preparation, a handover failure rate can increase and thus the service interruption time experienced by a User Equipment (UE) may increase.